612 STEVENSON— FORMATION OF COAL BEDS. [November 3, 



II. Autochthonous organic deposits. The Lake peat including (fl) 

 Phraginites peat, clear yellow, composed of fibrous roots with reeds 

 and some gyttja; {b) Equisetum peat, like the last in structure, but 

 the color is coal black. 



Telniatische. I. Swamp or Niedermoor peats, including (a) Magnocari- 

 cetum peat, consisting of sedges with Amblystegium as accessory, 

 yellow to yellow-brown ; {b) Amblystegium peat, consisting of stems 

 and leaves of that plant with some sedge constituents; (c) Bruchpeat, 

 red to black, amorphous humefied peat detritus, in situ, with identi- 

 fiable roots of sedges. 

 II. Hochmoor peats, (a) Cuspidatum peat, bright colored Sphagnum 

 cuspidatum and other water-loving mosses, with remains of Scheuch- 

 zeria, Carex and Eriophoruin. 



Semi-Terrestrische. I. (b) Vaginatum peat, Sphagnum with Eriophorum 

 vaginatum roots and stalks, these often making up one half of the 

 mass, humefied and dark colored; (r) Sphagnum peat in lenses with 

 Cladinti remains between clear brown layers of Sphagnum with 

 Eyi(iplioru]ii. 

 II. Forest peat, (a) Alder forest peat, red-black, amorphous, consists 

 of in situ deposited detritus of an alder swamp forest. Remains of 

 alder are recognizable; Cenococcum geopliilum abvmdant. 



Terrestrische. (b) Birch forest peat, like tlie last, but commonly dark 

 colored, deposited in a birch swamp forest; (c) Forest peat, rich in 

 Eriophorum and Sphagnu))i, as a rule, dark colored, almost always with 

 stumps and other remains of Scotch fir; (d) Forest mould, dark, 

 composed of wood detritus and grains of humus, witli stumps. 



All of these types from Lake peat down are autochthonous. The 

 upper Hmit of the basin or Hmnic deposits is at the normal Hue of 

 low water ; the shore or tehiiatic deposits are in the space covered 

 at high water, while the terrestrial are on forested areas, rarely cov- 

 ered with water. The alder swamp is the passage zone to the ter- 

 restrial. Von Post confirms IHytt's conclusions respecting the alter- 

 nation of dry and humid periods, and shows how, during the less 

 humid times, forests invaded the peat deposits and in some cases 

 covered the surface of pure peat with a dense growth. He presents 

 sections from a number of localities. ( )ne from the Asta moor shows 



A. Sphagnum peat, 85 centimeters, with, at 80 centimeters, a mass of 

 fir stumps rooted in the peat and with coaly matter between the stumps. 



B. Strongly humefied cuspidatum peat, 10 centimeters. 



C. Sedge peat, 30 centimeters, has much Sphagnum above. 



D. Alder and birch swamp forest peat, with small stumps of alder, 

 birch willow and a great quantity of Cenococcum geophilum, 15 centimeters. 



210 



